Hi, welcome to you and maybe also your son 
if your son is okay with mostly one-shots that however provide a way to carry over leveling and item progress, then maybe our regular open table games would be something for him?
There’s Requisite and Wowkeepers where about 6-10 open tables happen every Friday from 7-11pm and this week (and hopefully also in future weeks) there is also a Saturday noon game at the Sägewerk restaurant (currently full though).